Crematogaster scutellaris
Crematogaster scutellaris is a medium-sized species with a dark brown to black body contrasting with a shiny reddish head. The species is relatively common and dominant component of Mediterranean Europe’s ant fauna (Marlier et al., 2002), and is frequently introduced into central and northern Europe (Boer & Vierbergen, 2008; Klotz et al., 2008a; Rasplus et al., 2010). López-Sebastián (2004)provides a brief review of the biology of C. scutellaris. The nests are made of chewed wood and soil. in a large variety of microhabitats, including dead wood, human structures, and even stone walls (Soulié, 1956;1961 (1960)). The colony founding is independent, and colonies can live for several decades. All the workers are believed to be sterile (Casevitz Weulersse, 1991). The diet of the species is not well studied, but it is known to be an avid tender of hemipterans and will also take living and dead arthropods. Crematogaster scutellaris makes strong chemical trails used for recruiting large numbers of foragers that form conspicuous columns (Soulié, 1961 (1960)).
It had been presumed that the species was unable to establish outdoor colonies north of its native range on account of climatic conditions, but recent discoveries of such colonies in Germany (Heller, 2004)and the Netherlands (Boer & Vierbergen, 2008; Vierbergen, 1994)suggest establishment is possible and becoming more likely as the climate warms. In Germany, interceptions are most often associated with deliveries of cork and timber (Heller, 2004). Crematogaster scutellaris has also been intercepted as US ports of entry, though no records of establishment are known.
Inhabits human structures.
Diagnosis of worker among Antkey species. Head shape ovoid. Antenna 11-segmented. Antennal club 3-segmented. Antennal scapes not conspicuously short; easily extended beyond eye level. Antennal scrobe lacking. Eyes medium to large (greater than 6 facets) but distinctly less than half head length. Mandibles triangular. Pronotal spines absent. Propodeum armed with spines or teeth. Waist 2-segmented. Petiole flattened; lacking a distinct node; lacking peduncle; lacking large subpetiolar process. Petiole shape subrectangular. Postpetiole attached to upper surface of gaster. Head and mesosoma lacking abundant short flattened, semierect hairs. Head often reddish in color and contrasting with rest of body.
Crematogaster scutellaris can be easily distinguished from C. obscurata (which is introduced to the United States and commonly intercepted) by the following characters: (1) a 3-segmented club (versus 2-segmented); (2) a more trapezoidal petiole (versus triangular); (3) lack of abundant, flattened semierect hairs on its dorsal surfaces; (4) head often a reddish color that contrasts with rest of body.
Crematogaster obscurata
Native Range. Mediterranean Europe.
Introduced Range. Northern Europe: Germany, Netherlands.